It's usually difficult to tell the parakeet's sex until it's about 1 year old. Females usually have tan, white, pale blue, or brown ceres. The brown color is usually the more mature female. Males usually have dark blue ceres. The cere is the area above the beak where the nostrils are located.
Here is a good website with photos of male and female budgies:
http://www.budgieplace.com/mf.html
As for names, you didn't mention the color of your parakeets, but I'll go ahead and suggest some names as well as give you a website which may help. I like the names Stormy, Sunny, Snowy, Blizzard, Rio, Sky, Summer, Zeek, Peabody, Jasper, Bluebeard, Sparky.
http://www.funpetnames.com/parakeet-pet-names.html